An inverted Latin Cross divides the field into four quarters. The field is maroon, the traditional color of royalty and nobility, Prep's honored color. The inverted cross symbolizes the martyrdom of Saint Peter, the Prince of the Apostles and the Patron of the Prep.
Tradition tells us that the first Pope did not deem himself worthy to be crucified in the same position as his Master; so Peter died upside down, with his head in the dust of Rome. History proves that his gesture was not meaningless: within three centuries the city which had been the pagan capital of the world became the seat of the Christian empire.
The first quarter, the upper left hand section, bears the seal of the Society of Jesus, the Jesuit order that administers the school. The crown of thorns, encircling IHS (the first three letters of the name of "Jesus" in Greek recalls that Christ is a crucified King. The three nails represent the vows of poverty, chastity and obedience by which the Jesuit binds himself to the service of the "Victor King".
The second quarter, the upper right hand side, represents the Papal authority to which the Society is dedicated by special vow and by which the Christian people are assured of infallible guidance in faith and morals. The Crossed Keys are Christ's own symbols of that authority according to his words spoken to Peter, "I will give to thee the keys of the kingdom of Heaven..." The two lower quarters portray the fisherman's net and the apostolate of the Church and Society: "I will make you fishers of men".
The crest of the shield is the helmet of a Roman legionnaire, surmounting a wreath; it suggests the classical tradition of the Prep's educational system, and the location of the school. For the name Jersey is derived from Caesar; the original land grant in 1650 for the area that is now the state reads: "Said tract of land is hereafter to be called by the name or names of Nova Caesarea, or New Jersey".
The motto, "Sub umbra Petri" is translated "Under the shadow of Peter" and recalls the beautiful practice of the early Christians who brought their sick to Peter "so that when Peter passed, his shadow at least might fall on some of them". Under the same shadow Prep men live and learn.
Taken from Prep Men and Manners, the Prep student handbook, circa 1966.